1. Field of the Invention
The present invention relates to a method and system for detecting abnormal plasma discharge that is useful in, for example, detecting plasma leakage in a reactive ion etching (RIE) chamber.
2. Description of the Related Art
When performing processing in a chamber, such as reactive ion etching (RIE) within a plasma chamber, various problems can occur that affect the quality of the processing performed in the chamber. One problem that can occur is plasma leakage. More specifically, plasma leakage occurs when secondary plasma is formed in locations of the reactor other than the desired region. The source of the plasma leakage can be attributed to a variety of factors, some of which are difficult to monitor (e.g., baffle reworking, bad electrical contact of various parts, worn quartz rings, etc.). This plasma leakage degrades performance and sometimes results in failures because of problems such as vertical leakage and functional yield degradation. The invention described below addresses these issues.